Association of the thrombomodulin gene c.1418C>T polymorphism with thrombomodulin levels and with venous thrombosis risk.

OBJECTIVE: To investigate the association of the THBD c.1418C>T polymorphism, which encodes for the replacement of Ala455 by Val in thrombomodulin (TM), with venous thromboembolism (VTE), plasma soluble TM, and activated protein C levels. In addition, human umbilical vein endothelial cells (HUVEC) isolated from 100 umbilical cords were used to analyze the relation between this polymorphism and THBD mRNA and TM protein expression. APPROACH AND RESULTS: The THBD c.1418C>T polymorphism was genotyped in 1173 patients with VTE and 1262 control subjects. Levels of soluble TM and activated protein C were measured in 414 patients with VTE (not on oral anticoagulants) and 451 controls. HUVECs were genotyped for the polymorphism and analyzed for THBD mRNA and TM protein expression and for the ability to enhance protein C activation by thrombin. The 1418T allele frequency was lower in patients than in controls (P<0.001), and its presence was associated with a reduced VTE risk, reduced soluble TM levels, and increased circulating activated protein C levels (P<0.001). In cultured HUVEC, the 1418T allele did not influence THBD expression but was associated with increased TM in cell lysates, increased rate of protein C activation, and reduced soluble TM levels in conditioned medium. CONCLUSIONS: The THBD 1418T allele is associated with lower soluble TM, both in plasma and in HUVEC-conditioned medium, and with an increase in functional membrane-bound TM in HUVEC, which could explain the increased activated protein C levels and the reduced VTE risk observed in individuals carrying this allele.

Haplotypes of the EPCR gene, prothrombin levels, and the risk of venous thrombosis in carriers of the prothrombin G20210A mutation.

BACKGROUND: Haplotypes A1 and A3 in the endothelial protein C receptor (EPCR) gene are tagged by 4678G/C and 4600A/G respectively. We assessed whether these haplotypes modify the risk of venous thromboembolism in carriers of the prothrombin 20210A allele. DESIGN AND METHODS: We genotyped 4678G/C and 4600A/G in 246 20210A carriers: 84 venous thromboembolism propositi and 162 relatives (13 symptomatic), and in 140 relatives not carrying the 20210A variant. Prothrombin and soluble EPCR (sEPCR) levels were also measured. RESULTS: Among propositi, the mean age at first onset was lower in carriers (35 +/- 8 years) than non-carriers of the 4600G allele (44 +/- 14 years) (p = 0.004). The probability of being free of thrombosis at age 40 was lower in 20210A carriers with the EPCR 4600G allele (p = 0.015). The frequency of the 4600G allele (p=0.002) and the levels of prothrombin antigen (p = 0.002) and sEPCR (p < 0.001) were higher in the propositi than in their asymptomatic relatives. Multivariate analyses showed that the presence of the 4600G allele (OR = 2.5, 95% confidence interval 1.3-5.0), sEPCR > 147 ng/mL (2.8, 1.5-5.2) and prothrombin > 129% (3.8, 1.8-8.3) all increased the thrombotic risk. In bivariate analysis, including the 4600G allele and sEPCR > 147 ng/mL, only the latter remained associated with risk. CONCLUSIONS: These results show that in 20210A carriers the venous thromboembolism risk is influenced both by the actual prothrombin levels and by the EPCR A3 haplotype, via its effect on sEPCR levels.

Influence of lipids and obesity on haemorheological parameters in patients with deep vein thrombosis.

It is not well established whether haemorheological alterations constitute independent risk factors for deep vein thrombosis (DVT). We have determined in 149 DVT patients and in 185 control subjects the body mass index (BMI), the haemorheological profile: blood viscosity (BV), plasma viscosity (PV), fibrinogen (Fg), erythrocyte aggregation (EA), erythrocyte deformability (ED) and plasma lipids. In the crude analysis BMI, Fg, PV, EA, triglycerides (TG) and ApoB were statistically higher and HDL cholesterol (HDL-Chol) statistically lower in DVT patients than in controls. No differences in BV and ED were observed. After BMI adjustment, Fg, PV and EA remained statistically higher in DVT cases than in controls (P = 0.013; P = 0.012; P = 0.013; P = 0.028, respectively). When the risk of DVT associated with these variables (using cut-offs that corresponded to the mean plus one SD of the control group) was estimated, EA > 8.2 and PV > 1.28 mPa . s were significantly associated with DVT even further adjustment for lipids and obesity (OR = 2.78, P = 0.004; OR = 1.91, P = 0.024, respectively). However, PV did not remain statistically significant after additional adjustment for Fg. When we consider together all the analyzed variables in order to control every variable for each other, TG > 175 mg/dl (OR = 3,2, P = 0.004) and BMI > 30 kg/m(2) (OR = 3.5, P = 0.003), were also independently associated with a greater risk of DVT. Our results suggest that increased EA constitute an independent risk factor for DVT. However, when associated to hyperlipidaemia and obesity it further increases thrombotic risk.

Sialic acid is an inflammation marker associated with a history of deep vein thrombosis.

INTRODUCTION: Deep vein thrombosis (DVT) induces a systemic chronic inflammation and it has been associated with atherosclerosis. Increased levels of total sialic acid (TSA) have been shown to correlate with inflammation and atherosclerotic processes. The aim of this study was to investigate whether or not increased levels of TSA are associated with a history of DVT and with inflammation and coagulation markers, as well as with the lipid profile. MATERIALS AND METHODS: TSA, fibrinogen, C-reactive protein (CRP), fibrin D-dimer (D-dimer), prothrombin fragment 1+2 (F1+2), endogenous thrombin generation, cholesterol and triglycerides were measured in 68 patients who had suffered, in the previous 6-12 months, a first episode of idiopathic DVT, and in 68 age- and sex-matched healthy subjects. RESULTS: Levels of TSA, fibrinogen, CRP and D-dimer observed in patients were significantly higher than those detected in healthy subjects. TSA positively correlated with fibrinogen (R=0.47, p<0.01), cholesterol (R=0.46, p<0.01), triglycerides (R=0.38, p<0.01) and CRP (R=0.28, p<0.05). The logistic regression analysis confirmed that both high fibrinogen (> or =340 mg/dl) and cholesterol (> or =267 mg/dl) levels significantly and independently influence the TSA concentration. TSA levels above the 95th percentile of controls (>72 mg/dl) were detected in 33% of patients (OR=8.9; p<0.0001; 95% CI 2.4 to 31.7). CONCLUSIONS: Patients with a history of DVT had associated high levels of TSA. In these patients, TSA correlated to markers of inflammation activity and lipid profile. Thus, TSA appears to be a useful vascular inflammatory marker in idiopathic DVT.

Spontaneous renal subcapsular hematoma in an anticoagulated patient.

This is a case report of spontaneous subcapsular renal hematoma in an anticoagulated patient who was without excessive hypocoagulability and who was hemodynamically stable. Active bleeding was ruled out and a conservative treatment of discontinuing anticoagulant therapy was chosen. The patient was observed expectantly with serial abdominal computed tomography and abdominal ultrasound during her stay in the hospital. When diminution of the hematoma was detected, oral anticoagulation was resumed.

Effective and Safe Management of Oral Anticoagulation Therapy in Patients Who Use the Internet-Accessed Telecontrol Tool SintromacWeb.

BACKGROUND: Despite the existing evidence that highlights the benefits of oral anticoagulation therapy (OAT) self-testing and self-management by patients in comparison with conventional control, significant progress is still needed in the implementation of computer-based, Internet-assisted systems for OAT within health care centers. The telecontrol tool "SintromacWeb" is a previously validated system for OAT management at home, which is currently operative and accessed by patients through a hospital Web portal. OBJECTIVE: The intent of the study was to assess the effectiveness and safety of OAT management in patients using the SintromacWeb telecontrol system in reference to control in patients using the conventional system (management at the hematology department), in terms of time in therapeutic range (TTR) of International Normalized Ratio (INR). METHODS: In this observational prospective study, patients were identified by their physician and divided in two groups according to the OAT management system that they were already using (conventional control or telecontrol with SintromacWeb). For 6 months, patients were required to visit the hematology department every time their physician considered it necessary according to usual clinical practice. Sociodemographic and clinical variables for the study were collected at first visit (baseline) and at those visits closest to 2, 4, and 6 months after first visit. RESULTS: A total of 173 patients were evaluated, 87 with conventional control and 86 with telecontrol. Follow-up time was a median of 6.3 (range 5.2-8.1) months. The average time of OAT treatment prior to enrollment was 9.2 (SD 6.4) years. Patients in the telecontrol group tested their INR a median of 21 (range 4-22) days versus a median of 35 (range 14-45) days in patients in the conventional control group (P<.001). TTR in the telecontrol group was 107 (SD 37) days versus 94 (SD 37) days in the conventional control group (an increase of 12.6%; P=.02). In all visits, the percentage of TTR was higher in the telecontrol group (at the third visit: 59% vs 48%; P=.01). Higher TTR (positive coefficient) was associated with patients under OAT telecontrol (P=.03). Under-anticoagulation (INR<1.5) and over-anticoagulation (INR>5) were observed in 34 (19.7%, 34/173) and 38 (22.0%, 38/173) patients, respectively (no differences between treatment groups). Seven thrombotic and/or bleeding events were serious, 12 were non-serious, and most of them (5 and 10, respectively) occurred in the conventional control group. CONCLUSIONS: In clinical practice, OAT management with the Internet-based tool SintromacWeb is effective and safe for those patients who are eligible for OAT telecontrol.

Factor V Leiden and prothrombin G20210A mutations in young adults with cryptogenic ischemic stroke.

The association between factor V Leiden (FVL) and prothrombin G20210A (PT 20210) mutations and ischemic stroke remains controversial, particularly in young adults with cryptogenic stroke. Prevalence of FVL (4.1%) and PT 20210 (8.2%) mutations was assessed in 49 patients under 50 years with cryptogenic stroke and compared with controls. Odd ratio (OR) for cryptogenic stroke was 2.62 (95% CI, 0.49-13.95) for FVL and 3.75 (95% CI, 1.05-13.34) for PT 20210 and 3.28 (95% CI, 1,17-9.20) for some recognized genetic thrombophilic defect. Moreover, the OR for cryptogenic stroke in young women using oral contraceptives (OC) was 3.59 (95% CI, 1.28-10.5). When some genetic thrombophilic defect was associated with OC, the OR was much higher (OR: 14.27; 95% CI, 0.66-309.99). Our results suggest that in the Mediterranean populations the PT 20210 mutation, but not FV Leiden, is a risk factor for cryptogenic stroke in young adults. OC use is also a significant risk factor for cryptogenic stroke, which is increased in women with some genetic thrombotic risk factor.

Prothrombin G20210A mutation and oral contraceptive use increase upper-extremity deep vein thrombotic risk.

The role played by a hypercoagulable state, either inherited or acquired, in the pathogenesis of upper-extremity deep vein thrombosis (UEDVT) remains a question of debate. We performed a case-control study including 79 patients with a first objectively confirmed episode of UEDVT, 31 secondary and 48 primary, and 165 healthy controls. Nine patients (11.4%) with UEDVT were carriers of the prothrombin G20210A mutation vs. six (3.7%) in controls; P = 0.025, OR: 3.39 (95% CI 1.16 to 9.88). No statistical difference was observed between cases and controls for the factor V Leiden mutation, AT, protein C or protein S deficiency and anticardiolipin antibodies (ACAs). Thirteen (35.1%) UEDVT patients were oral contraceptive (OC) users vs. 12 (16%) controls; P = 0.020, OR: 2.89 (95% CI 1.16-7.21). When secondary UEDVT patients were compared with controls, no differences were observed in any of the risk factors analysed. On the other hand, when primary UEDVT was considered, six (12.5%) patients were carriers of the prothrombin G20210A mutation vs. six (3.7%) controls; P = 0.031, OR: 3.76 (95% CI 1.15-12.26). Regarding ACAs, a borderline statistical significance was observed when primary UEDVT was compared with controls, P = 0.048; OR: 4.88 (95% CI 1.05-22.61). In primary UEDVT, 52% of the fertile women were OC users vs. 16% of controls; P = 0.001, OR: 5.78 (95% CI 2.13-15.67). When the interaction of both factors, i.e. prothrombin G20210A mutation and OC intake, were considered, the risk increased markedly, indicating a synergistic effect as observed with other thrombotic locations. In patients with primary UEDVT screening for antithrombin, protein C and protein S deficiency and APC resistance would not be justified, although it might be reasonable to determine the carrier status of the prothrombin G20210A mutation only in OC users.

Contribution of polymorphisms in the endothelial protein C receptor gene to soluble endothelial protein C receptor and circulating activated protein C levels, and thrombotic risk.

Endothelial cell protein C receptor (EPCR) enhances the generation of activated protein C (APC) by the thrombin-thrombomodulin complex. A soluble form of EPCR (sEPCR), which is generated by metalloprotease activity, is present in plasma. The distribution of sEPCR levels in healthy populations is bimodal. Previously, we described two polymorphisms in exon 4 of the EPCR gene, 4600A/G that encodes the substitution of Ser219 by Gly in the transmembrane region of EPCR and 4678G/C in the 3'-UT region. The aim of this study was to investigate the relationship between these two polymorphisms and plasma sEPCR and APC levels and risk of venous thrombosis. We genotyped 401 healthy controls from the Spanish population and measured their plasma sEPCR and APC levels. Carriers of the 4600AG genotype had significantly higher sEPCR levels than those with the AA genotype, while the 4678CC genotype was associated, to a lesser extent, with elevated APC levels. To assess the effect of these polymorphisms on the risk of thrombosis, we genotyped 405 patients with venous thromboembolism. The frequency of the 4600AG genotype was very similar in patients and controls (p=0.975), whereas the 4678CC genotype was significantly more frequent in controls than in patients (p=0.008). In multivariate analysis, carriers of the 4678CC genotype had a decreased risk of thrombosis (OR=0.61, p=0.009). These data indicate that individuals carrying the 4600AG genotype have high sEPCR levels but do not have an increased risk of thrombosis, whereas individuals carrying the 4678CC genotype have higher APC levels and lower risk of venous thromboembolism.

Is family history sufficient to identify women with risk of venous thromboembolism before commencing the contraceptive pill?

Oral contraceptives (OGs) increase risk of venous thromboembolic disease (VTE). The incidence of thomboembolic disease in healthy young women who are not taking OCs is 0.4-0.8/10,000, and in healthy young women using OCs, it is 3-4/10,000. To assess whether a family history of thromboembolism is a suitable tool to identify women who should not be given OCs, 50 women who suffered a VTE while taking OCs were studied. Only 16% of these women had family history which is why in our opinion, it is not a sufficient safeguard to recommending the use of OCs.

Biological risk factors for deep vein trombosis.

Hypercoagulable states due either to inherited or acquired thrombotic risk factors are only present in approximately half of cases of DVT, but the causes in the other half, remain unknown. The importance of biological risk factors such as hyperlipidemia, hypofibrinolysis and hemorheological alterations in the pathogenesis of DVT has not been well established. In order to ascertain whether the above mentioned biological factors are associated with DVT and could constitute independent risk factors, we carried out a case-control study in 109 first DVT patients in whom inherited or acquired thrombophilic risk factors had been ruled out and 121 healthy controls age (42+/-15 years) and sex matched. From all the biological variables analyzed (cholesterol, triglycerides, glucose, fibrinogen, erythrocyte aggregation, hematocrit, plasma viscosity and PAI-1) only fibrinogen concentration reached a statistically significant difference on the comparison of means (290+/-73 mg/dl in cases vs 268+/-58 mg/dl in controls, p<0.05). After this continuous variables were dichotomized according to our reference values, the percentage of cases with cholesterolemia >220 mg/dl, hematocrit >45% and fibrinogen >300 mg/dl was higher in cases than in controls: 38% vs 22%; p<0.01; 43% vs 27%; p<0.05; 36% vs 23%; p<0.05, respectively. The percentage of cases with PAI-1 values >30 ng/ml, 37% vs 25% was borderline significant; p=0.055. Multivariate logistic regression analysis showed that cholesterolemia >220 mg/dl and fibrinogen >300 mg/dl constitute independent predictors of venous thrombotic risk. The adjusted OR's were 2.03 (95% CI; 1.12-3.70) for cholesterolemia and 1.94 (95% CI; 1.07-3.55) for fibrinogen. When these two variables combined DVT risk rose about fourfold (3.96; p<0.05). Our results suggest that hypercholesterolemia and hyperfibrinogenemia should be added to the list of known DVT risk factors and we recommend adopting measures to decrease these variables in the population with a high risk of DVT.

Implementation of SintromacWeb(R), a new internet-based tool for oral anticoagulation therapy telecontrol: Study on system consistency and patient satisfaction.

Most computer- or internet-assisted systems for oral anticoagulation therapy (OAT) telemanagement have limitations when it comes to implementation within a healthcare center. It was the objective of this study to evaluate convenience and patient satisfaction with the use of SintromacWeb, a new OAT telecontrol system, compared with the conventional control. SintromacWeb consists of a point-of-care device for patient international normalized ratio (INR) self-testing and software that allows internet mediated interaction with physicians. Patients initiated the use of SintromacWeb and were followed up during a three-month period. A score-based questionnaire was completed in three controlled visits, and data were subsequently analysed. A total of 102 patients were enrolled. At first visit, 55.7% of the patients had their INR within normal range, and 64.9% at the final visit. Internal consistency of the questionnaire was good (Cronbach's a: 0.79). Scores in the questionnaire were independent of patient's age, education level, working status and INR value. The most valued features of SintromacWeb were: fewer visits to the hospital, simplicity and convenience of the system, and time administration for control tasks (86.7%, 82.7% and 77.6% of very satisfied patients, respectively). Also, patients showed indifference or were dissatisfied with the conventional system. At the final visit, 99% of patients declared that they were satisfied with their OAT control. Moreover, all patients continued using SintromacWeb after completion of the study. In conclusion, SintromacWeb telecontrol is a new model for management of anticoagulated patients. It was highly accepted and can be used by all patients regardless of their sociodemographic characteristics.